Having seen several EPR over-read situations -doesn't take much take much damage to the fan/core rake to cause this. Famous one was a Tech Log write up, "EPR reading correct but all other parameters low". IMHO EPR indication only has a place if the fuel control uses EPR as the primary control parameter...otherwise N1 is more reliable...but not necessarily as accurate.
Go for N1 indication- control on a modern engine is using a 'model'with inputs of speeds,EGT,ff etc etc and no one controlling parameter anyway....and besides it's super easy to change a speed probe (Rollers exempt as per usual!?!) and difficult to fix a damaged EPR rake.
Ground Checked Satis- Please report futher.